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Biomedical subjects

W R Bell

Publications and source records attributed to W R Bell.

At least 127 records · Page 7Linked to original sources
PubMed1980

Heparin-associated thrombocytopenia: a comparison of three heparin preparations.

We performed a prospective, double-blind study of the incidence of thrombocytopenia in 149 patients randomly assigned to treatment with one of three heparin preparations--from bovine lung from intestinal-mucosa A, or from intestinal-mucosa O. Thrombocytopenia developed in 21 patients (platelets, < 100 x 10(9) per liter): 13 of the 50 receiving bovine lung heparin, four of 45 receiving intestinal-mucosa-A heparin, and four of 54 receiving intestinal-musoca-O heparin (P < 0.005). There was a significantly increased incidence of thrombocytopenia in the bovine-lung group (P < 0.002); estimated incidence rates after nine days of treatment were 24 per cent in this group and 7 per cent in the combined intestinal-mucosa A and O groups. Thrombocytopenia appeared in the bovine-lung group on days 3 to 16, in the intestinal-mucosa-A groups on Days 4 to 12, and in the intestinal-mucosa-O group on Days 3 to 7; it disappeared in all groups three to eight days after discontinuation of heparin. A total of 121 patients were subsequently given warfarin for four to six months, and thrombocytopenia was not observed.

Animals↗
PubMed1980

Multiple coronary thromboses in previously normal coronary arteries: a rare cause of acute myocardial infarction.

This report describes an unusual form of myocardial infarction in a 44-year-old woman who was found to have two proximal coronary artery thrombi with otherwise normal coronary arteries. An interesting feature of her history was that the coronary events occurred in association with thrombocytopenia and heparin treatment. Two other clinical reports of patients who developed thrombocytopenia and myocardial infarction while receiving heparin have been identified, and the possibility that these thrombi were secondary to a coagulation abnormality associated with heparin is considered.

Adult↗
PubMed1980

Venous thrombosis and splenic rupture in paroxysmal nocturnal hemoglobinuria.

A patient with an 11 year history of paroxysmal nocturnal hemoglobinuria presented with severe abdominal pain. On admission, the hematocrit value was 30 per cent and unchanged from repeated measurements during the previous three years. Abdominal angiography identified extensive thromboses of the splenic and portal venous systems. After initial improvement on heparin therapy, the patient experienced additional abdominal crises. A ruptured and multifragmented spleen was removed at the time of exploratory laparotomy. Postoperatively, after a several days' interval of improvement, the patient experienced additional thrombotic episodes of the abdomen, upper extremities and cerebral cortex. The latter was associated with disabling nerve paralysis. With continuous intravenous heparin plus steroid therapy, the patient's condition improved progressively. Despite the numerous thrombotic episodes during the prolonged hospital course, no hemolytic episodes were observed. This is the first report of documented splenic rupture in a patient with paroxysmal nocturnal hemoglobinuria.

Adult↗
PubMed1980

Disseminated intravascular coagulation and portal hypertension following pancreatic islet autotransplantation.

A patient undergoing subtotal pancreatectomy and intraportal islet tissue autotransplantation for chronic pancreatitis developed severe portal hypertension (49 cm of H(2)O) and acute disseminated intravascular coagulation (DIC). In an attempt to identify the cause of these problems, portal pressure and the activities of the coagulation and fibrinolytic systems were studied in dogs undergoing intraportal autotransplantation of islet tissue. Following intraportal injection of the pancreatic tissue in five control dogs, the portal pressure rose to a maximum of 43.2 cm of H(2)O +/- 2.4 and major coagulation abnormalities occurred. The mean hematocrit value fell to 18% +/- 8.6, the mean platelet count to 218,000 +/- 31,000, the mean plasma fibrinogen to 40 mg/dl +/- 18, and the mean euglobulin clot lysis time (ECLT) to 25 min +/- 4. Partial thromboplastin time (PTT) became prolonged (233 secs +/- 30) and significant quantities of fibrinogen-fibrin degradation products (FDP-fdp) (1:128 +/- 32) appeared. These changes indicate the development of DIC probably secondary to significant amounts of tissue thromboplastin detected in the tissue homogenate infused at time of autotransplantation. In a group of seven dogs in whom heparin and Trasylol (aprotinin) were added to the pancreatic tissue at the time of transplantation, portal pressure rose only to a peak of 28.3 cm of H(2)O +/- 3.6 and no significant abnormalities occurred in mean hematocrit value, plasma fibrinogen, platelet count or ECLT. Minor prolongation of PTT occurred secondary to the activity of heparin. FDP-fdp (1:16) were present transiently during tissue injection. Four patients in whom heparin and Trasylol were added to the pancreatic tissue at the time of autotransplantation developed only minor elevations of portal pressure (mean 15.5 cm of H(2)O) without intravascular coagulopathy.

Animals↗
PubMed1980

Essential thrombocythaemia.

The results of detailed studies of 3 patients with essential thrombocythaemia (ET) are presented. Qualitative tests of platelet function were abnormal, and autologous platelet survivals were diminished. Megakaryocyte ploidy distribution analysis showed an increased proporttion of cells with high ploidy, and buoyant density distribution analysis showed increased proportions of less dense platelets. Ultrastructural studies of the platelets showed proliferation of the dense tubular system with deficiency of the surface-connected canalicular system. Megakaryocyte electron microscopy showed abnormal distribution of demarcation membrane complex and granules. The precise functional abnormality of the platelets in ET has not yet been defined, but a release defect of variable severity with corresponding morphological abnormalities of dense tubular and surface-connected canalicular systems, seems the most likely explanation.

Adult↗
PubMed1980

Disseminated intravascular coagulation.

Disseminated intravascular coagulation (DIC) is a clinico-pathological syndrome of variable expression, resulting from uncontrolled simultaneous activation of the coagulation and fibrinolytic systems. DIC can be initiated in a variety of different ways. Additional studies are needed to determine the importance of vascular endothelial damage, hemodynamic alterations and the role of naturally occurring inhibitors of hemostasis. Progressive increase in our understanding of the mechanisms involved in triggering DIC will improve our therapeutic measures in the rational management of these patients. Absolutely essential in the successful management of patients with DIC is identification and control of the underlying illness.

Disseminated Intravascular Coagulation↗
PubMed1980

Respiratory failure in acute pancreatitis: the role of free fatty acids.

Hypertriglyceridemia has been noted in patients with acute pancreatitis and respiratory failure. Utilizing an isolated, perfused, canine pulmonary lobe, the effect of triglyceride infusion on pulmonary function was evaluated. When heparin was used to anticoagulate the perfusion circuit, the addition of triglyceride to the autologous blood perfusate resulted in massive weight gain (226 gm), intrapulmonary shunting (36%), and a marked drop in pulmonary compliance (congruent to 50%). Heparin activates lipoprotein lipase, and therefore some triglyceride in the perfusate was lipolyzed with a resultant increase in serum free fatty acids (FFAs) to 253 mumole/dl. When anticoagulation of the perfusion circuit was accomplished by defibrinogenation with Arvin, the addition of triglyceride to the autologous blood perfusate caused minimal weight gain (28 gm), no intrapulmonary shunting, and only a slight decrease in pulmonary compliance (22%). Arvin has no effect on lipoprotein lipase, and the FFA level in the perfusate remained normal (less than 70 mumole/dl). Thus it appears that FFA release secondary to the action of pulmonary lipoprotein lipase on blood triglyceride is the important pathogenic step in the induction of respiratory failure in this model.

Acute Disease↗
PubMed1979

The effect of chlorotrianisene as postpartum lactation suppression on blood coagulation factors.

Coagulation changes and increased risk of thromboembolic disease may occur in association with estrogen administration. The puerperium is also a high-risk period for thromboembolism, and estrogen administration at this time may increase this risk. Patients with congenital deficiency of antithrombin III have recurrent venous thromboembolic disease, suggesting that low levels of this factor may be associated with "hypercoagulability" states. We studied 50 postpartum patients who received chlorotrianisene (Tace) or placebo for lactation suppression in a prospective, double-blind, randomized fashion. Antithrombin III values were significantly lower on the third day post partum in the treated group compared to the placebo group (p less than 0.05). In addition, our clinical data from a total of 99 patients support the previous evidence that estrogens delay rather than prevent breast engorgement. Thus, with questionable benefit and a possible increased thromboembolic risk, it would appear prudent to discontinue the practice of estrogen administration for lactation suppression.

Adult↗
PubMed1979

Accuracy of screening for pulmonary embolism in the emergency room.

Pertinent historical, clinical, and laboratory findings were recorded for 37 consecutive patients who presented to the emergency room complaining of shortness of breath and chest pain but without evidence of coronary insufficiency, pneumonia, or musculoskeletal injury. 13 had pulmonary embolism suggested by lung scan with or without pulmonary angiogram, or, in 2 cases, by right heart catheterization. As a group, these patients in whom embolism was judged probable approached fairly closely the profiles of previous studies of patients with documented pulmonary emboli. Nonetheless, they differed very little, and in no clinically useful way short of lung scans and invasive studies, from the remaining 24 patients in whom embolism was judged unlikely. In the population served by this emergency room, which has a high morbidity from chest diseases and putative predisposing conditions to pulmonary embolism, screening patients for high and low probability groups for this diagnosis cannot be done on clinical grounds alone. Six-projection ventilation-perfusion lung scanning may be the only acceptable screening examination, and should be available directly from the emergency room in hospitals with an active emergency service.

Emergency Service, Hospital↗
PubMed1979

The heart and cardiac conduction system in thrombotic thrombocytopenic purpura. A clinicopathologic study of 17 autopsied patients.

The relation between the heart lesions of thrombotic thrombocytopenic purpura and clinical cardiac dysfunction was studied in 17 autopsied patients. Thirteen of the 17 patients had extensive small-vessel thromboses and in some instances hemorrhages and focal necroses within the heart. Congestive heart failure was present in nine of the 17 patients. Thrombotic microcirculatory cardiac lesions and anemia-related high cardiac output may have contributed to cardiac dysfunction. Serial histologic sections of the cardiac conducting system in 10 patients showed microthrombi in seven and associated hemorrhages in five. Lesions were localized to the atrioventricular node and His bundle parts of the system with sparing of the sinoatrial node and bundle branches. Two patients had electrocardiographic evidence suggesting lesions within conducting tissues. Thrombi and hemorrhages are common findings in the conducting tissues in thrombotic thrombocytopenic purpura and may account for cardiac arrest or transient rhythm disturbances.

Adolescent↗
PubMed1979

The effect of homologous thrombin and fibrinogen degradation products on fibrinogen synthesis in rabbits.

The effect of intravenous infusions of purified homologous FDP and thrombin on fibrinogen synthesis was evaluated in rabbits. De novo fibrinogen production was measured by the rate of incorporation of 75SeM into circulating fibrinogen. After receiving either 100 or 200 NIH U/kg purified homologous thrombin over 1 hr, rabbits demonstrated threefold and fivefold increases in fibrinogen synthesis, respectively. A correlation between the titers of FDP-fdp and the degree of fibrinogen synthesis was evident. Prior administration of epsilon-ACA prevented the accelerated synthesis of fibrinogen induced by thrombin and inhibited the appearance of FDP-fdp in serum. epsilon-ACA did not interfere with normal fibrinogen production. Fibrinogen synthesis was assessed following infusions of FDP prepared by vitro by digestion of rabbit fibrinogen with plasmin and subsequently identified on SDS-polyacrylamide gels. Preparations which contained predominantly stage 2 intermediate (X, Y, D, and E) or stage 3 final (D and E) fragments accelerated fibrinogen synthesis, whereas those containing predominantly stage 1 fragment X did not. Prior treatment with epsilon-ACA did not alter these results. Infusion of the supernatants derived from immunoprecipitation of the FDP by either anti-rabbit fibrinogen antibody or specific anti-human D and E antibodies significantly diminished the enhanced fibrinogen synthesis induced by the unadsorbed materials. These experiments suggest that the accelerated fibrinogen synthesis induced by thrombin is mediated by FDP, with fragments D and E appearing to be the most potent.

Aminocaproic Acid↗
PubMed1979

Platelet and fibrinogen production: relative sensitivities to endotoxin.

The relative sensitivities of platelet and fibrinogen production to endotoxin were determined in male New Zealand rabbits. E. coli endotoxin was administered in single intravenous doses of 0.1 to 50.0 mu/g/kg body mass. 75SeM was injected 5, 12, or 18 hr after endotoxin, and the percent incorporation into platelets and fibrinogen was used to measure thrombopoiesis and fibrinogen synthesis. Leukopenia occurred after the infusion of endotoxin at all dose levels; the lowest dose that caused thrombocytopenia was 0.5 microgram/kg. Endotoxin was detected with the Limulus test in plasma of animals that received 5 to 50 microgram/kg. The stimulation of fibrinogen and platelet production, as well as the postinfusion decrease in platelet count, correlated directly with the log of the dose of endotoxin infused. The lowest dose of endotoxin that stimulated platelet and fibrinogen production was 0.5 microgram/kg. In animals that received this dose of endotoxin, increased fibrinogen production was detected only when 75SeM was injected 5 hr later. In animals injected 5, 12, or 18 hr later. Increased platelet production was detected at these two doses only when 75SeM was injected 18 hr after endotoxin. The data indicate that fibrinogen and platelet production have similar sensitivities to endotoxin, although the time course of stimulation is different for these two blood components.

Animals↗
PubMed1979

Regulation of fibrinogen biosynthesis: effect of fibrin degradation products, low-molecular-weight peptides of fibrinogenolysis, and fibrinopeptides A and B.

Fibrinogen synthesis in rabbits was evaluated following intravenous infusions of stage 3 degradation products of homologous fibrinogen or fibrin, prepared in vitro. Fibrinogen production was measured by determining the rate of appearance of 75SeM into circulating fibrinogen. Fibrinogen synthesis increased threefold after the administration of stage 3 FDP (D and E), dialyzed to remove LMW digestion fragments, In contrast, the fdp obtained by plasminolysis of crosslinked thrombin clots or of noncrosslinked ancrod or thrombin clots failed to enhance basal fibrinogen production. Accelerated fibrinogen production was not accompanied by alterations in haptoglobin concentration or by increased incorporation of 75SeM into haptoglobin. Fibrinogen synthesis was not increased after infusions of FPA and FPB.

Ancrod↗